Morphological studies on machined implants of commercially pure titanium and titanium alloy (Ti6Al4V) in the rabbit

The aim of this study was to evaluate the bone response to commercially pure titanium grade I and titanium alloy grade V (90% Ti, 6% Al, and 4% V, depicted Ti6Al4V) after 8 weeks in rabbit tibia. Interference microscopy and scanning electron microscopy were used for surface analyses. Transmission electron microscopy (TEM) was used for evaluation of surface crystallinity and chemistry after preparation of ultrathin sections using focused ion beam (FIB) microscopy. Three different embedding resins commonly used for histological preparation were evaluated with respect to adaptation to a turned implant surface. Epoxy Agar 100 resin and acrylic Technovit 7200 resin showed low separation while acrylic LR White resin showed large separation at the interface. The retrieved specimens were embedded in acrylic Technovit 7200 resin after fixation and dehydration. The histological evaluation revealed osseointegration for both c.p. titanium grade I and Ti6Al4V alloy, but no quantitative differences in bone contact and bone area were detected. Because a separation of implant and tissue occurred in the interface between implant and bone embedded in acrylic Technovit 7200 resin, additional factors related to implant surface properties and technical procedures are likely to influence the possibilities to prepare ultrathin sections by FIB.